Replying to Some car audio questions? Wiring question too. Please help me out!

Hello all!
I have a 2006 BMW 325i and I was wondering what a good quality cheap radio that will fit is. I am getting two 12" subwoofers, so is there a specific one that I need to get to be able to hook the subs up? I am not that good with car audio so I needed some opinions. I would like it to be under $150.

Also, will I need to get an amp also, or is just getting the subs ok?

Is there any good way to wire the subs from the trunk to the radio??

Sorry I have a lot of questions! Any other info I might need to know would be greatly appreciated!